Attendees of the "What's in Your Smartphone" panel at Legalweek 2019 walked away with a handy nugget of legal advice for their troubles.

"If you're going to commit a crime, maybe it's best to leave your phone at home," said panelist Anna Clark, a partner at Phillips Lytle.

The rest of session tended to bear her out on that one, devoting an hour to the many, many, many different ways that cellphone data can be used during the course of an investigation to help shed light on a criminal or legal matter.

Warren Singh, supervisor of practice technology consulting at Latham & Watkins, used the example of a man who was harassing an ex-girlfriend. Geotagged selfies inside his phone helped to establish he had been in her vicinity.

"Understanding how clients are using these devices has really caused us to pause in how we approach cellphone data," Singh said.

But getting that data is not without it's hurdles. Employees who use personal phones at work, for example, may resist attempts by employers to retrieve data during the course of an investigation. Clark said that courts are generally requiring that this information be turned over.

Brian Morrison, principal e-discovery analyst at Liberty Mutual, perhaps has a clearer path forward than employers who are trying to obtain information from an employee's personal mobile device. He's typically dealing with phones that are COPE (corporate-owned, personally enabled).

"One of the big issues is how do you get the phone? Well, it's our phone, so hand it over," Morrison said.

Once the phone comes into their possession the investigation becomes about tracking patterns in the data. What is the first/last call the person makes every day? How do they label their contacts? A derogatory name, for example, could add context to a communication.

Patterns are also useful for identifying code words hidden inside messages.

"When people start saying 'Merry Christmas' and it's August that throws up some flags," Morrison said.

Laura Roman, a panelist and litigation operations and e-discovery specialist with the New York Stock Exchange, pointed out how data that is conspicuously absent from a mobile device can help paint a picture, too. In the case of financial transaction, for instance, a lack of data pertaining to Venmo, a mobile payment service, could be considered an oddity.

According to Roman, stock exchange investigations had previously revolved around trading data. Only in the last year have they started looking more closely at information and messages collected from mobile devices.

"We're starting to pay closer and closer communications to those communications instead of email," Roman said.